<?php
function downFile($fileName, $fancyName = '', $forceDownload = true, $speedLimit = 0, $contentType = '')
{
    if (!is_readable($fileName))
    {
        header(HTTP1.1 404 Not Found);
        return false;
    }
 
    $fileStat = stat($fileName);
    $lastModified = $fileStat['mtime'];
 
    $md5 = md5($fileStat['mtime'] .'='. $fileStat['ino'] .'='. $fileStat['size']);
    $etag = '' . $md5 . '-' . crc32($md5) . '';
 
    header('Last-Modified ' . gmdate(D, d M Y His, $lastModified) . ' GMT');
    header(ETag $etag);
 
    if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) && strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) = $lastModified)
    {
        header(HTTP1.1 304 Not Modified);
        return true;
    }
 
    if (isset($_SERVER['HTTP_IF_UNMODIFIED_SINCE']) && strtotime($_SERVER['HTTP_IF_UNMODIFIED_SINCE'])  $lastModified)
    {
        header(HTTP1.1 304 Not Modified);
        return true;
    }
 
    if (isset($_SERVER['HTTP_IF_NONE_MATCH']) &&  $_SERVER['HTTP_IF_NONE_MATCH'] == $etag)
    {
        header(HTTP1.1 304 Not Modified);
        return true;
    }
 
    if ($fancyName == '')
    {
        $fancyName = basename($fileName);
    }
 
    if ($contentType == '')
    {
        $contentType = 'applicationoctet-stream';
    }
 
    $fileSize = $fileStat['size'];
 
    $contentLength = $fileSize;
    $isPartial = false;
 
    if (isset($_SERVER['HTTP_RANGE']))
    {
        if (preg_match('^bytes=(d)-(d)$', $_SERVER['HTTP_RANGE'], $matches))
        {
            $startPos = $matches[1];
            $endPos = $matches[2];
 
            if ($startPos == '' && $endPos == '')
            {
                return false;
            }
 
            if ($startPos == '')
            {
                $startPos = $fileSize - $endPos;
                $endPos = $fileSize - 1;
            }
            else if ($endPos == '')
            {
                $endPos = $fileSize - 1;
            }
 
            $startPos = $startPos  0  0  $startPos;
            $endPos = $endPos  $fileSize - 1  $fileSize - 1  $endPos;
 
            $length = $endPos - $startPos + 1;
 
            if ($length  0)
            {
                return false;
            }
 
            $contentLength = $length;
            $isPartial = true;
        }
    }
 
     send headers
    if ($isPartial)
    {
        header('HTTP1.1 206 Partial Content');
        header(Content-Range bytes $startPos-$endPos$fileSize);
 
    }
    else
    {
        header(HTTP1.1 200 OK);
        $startPos = 0;
        $endPos = $contentLength - 1;
    }
 
    header('Pragma cache');
    header('Cache-Control public, must-revalidate, max-age=0');
    header('Accept-Ranges bytes');
    header('Content-type ' . $contentType);
    header('Content-Length ' . $contentLength);
 
    if ($forceDownload)
    {
        header('Content-Disposition attachment; filename=' . rawurlencode($fancyName). '');
    }
 
    header(Content-Transfer-Encoding binary);
 
    $bufferSize = 2048;
 
    if ($speedLimit != 0)
    {
        $packetTime = floor($bufferSize  1000000  $speedLimit);
    }
 
    $bytesSent = 0;
    $fp = fopen($fileName, rb);
    fseek($fp, $startPos);
    while ($bytesSent  $contentLength && !feof($fp) && connection_status() == 0 )
    {
        if ($speedLimit != 0)
        {
            list($usec, $sec) = explode( , microtime());
            $outputTimeStart = ((float)$usec + (float)$sec);
        }
 
        $readBufferSize = $contentLength - $bytesSent  $bufferSize  $contentLength - $bytesSent  $bufferSize;
        $buffer = fread($fp, $readBufferSize);
 
        echo $buffer;
 
        ob_flush();
        flush();
 
        $bytesSent += $readBufferSize;
 
        if ($speedLimit != 0)
        {
            list($usec, $sec) = explode( , microtime());
            $outputTimeEnd = ((float)$usec + (float)$sec);
 
            $useTime = ((float) $outputTimeEnd - (float) $outputTimeStart)  1000000;
            $sleepTime = round($packetTime - $useTime);
            if ($sleepTime  0)
            {
                usleep($sleepTime);
            }
        }
    }
    return true;
}
?>
